This invention relates to a luminous material for use in fishery which is characterized by luminous bacteria carried in or applied to a bait and also to a method for making such luminous material.
The availability of luminous baits has been widely known and artificial baits containing fluorescent substances have been already put on the market. The effectiveness of the luminous bait is generally accepted by a fact that, on inspection of the stomach of nocturnal tunnies, luminous fishes or cuttlefishes are often found in the stomach.
Thus, in order to render baits luminous, there have been proposed several methods using electric means and fluorescent substances. However, the luminescence by electrical means undesirably needs an electric supply such as a battery or cell, while the use of fluorescent substances requires an additional light source, i.e., the fluorescent substance is very short in luminescent time when placed in the dark where no light source is present. Thus, these prior methods have the fundamental and vital disadvantages.
In order to overcome these disadvantages, luminous baits have been proposed using chemical luminous substances. However, such luminous baits have a number of drawbacks, of which the toxicity of the luminous bait due to the use of the chemical luminous substances is one of the most serious problems. If, for example, one eats fishes which take the bait containing chemical luminous substances, he has a great possibility of indirectly taking the substances per se, or metabolites or decomposed products thereof. The intake of such toxic chemical substance is not favorable from a viewpoint of health.